How do planes get rid of poo

Long distant flying can be a great time to sit back, relax and enjoy a few movies or books. But even though you are taking a break from the fast-paced life, your bowels are still functioning as normal and have needs. Even though the compact bathroom isn’t exactly like your siphon toilet at home, it does the trick. But what exactly happens to all the excrements? Do they make their way down to unfortunate houses below? Not exactly. Technology has come quite a long way.

brown pau via Visual Hunt

Pilots during the Second World War used “slop buckets” as their loos. Either the excrements would slosh around during the flight or, if that became too messy, the buckets would be dumped out the window. This wasn’t ideal for anyone involved.

Over time, the toilets on the planes started using the blue liquid called Anotec, which assisted in moving the waste from the bowl down to the storage tanks below. There were a few problems with this solution though. There was a large increase in the added weight to the flight which meant that the plane wouldn’t be able to hold as many passengers. But perhaps more importantly these tanks tended to leak and would escape the hull where they would form a frozen ball of excrements. When the plane was at lower a lower altitude, the blue ice would thaw and hit someone or something below.

While it is somewhat humorous to think about, victims of this blue ice did not think so. Between 1979 and 2003 there have been 27 cases in the U.S. where wads of “blue ice” fell and damaged things such as cars and roofs.

Eventually in 1975 a man named James Kemper patented the idea of creating a “vacuum waste system”. This used on a fraction of water and depended mostly on the non-stick coating of the bowl and the vacuum suction. When visitors push the flush button, a valve opens up at the bottom of the toilet bowl and the pneumatic vacuum sucks down the contents. They head down to the plane’s sewer line where there is a 200 gallon holding tank. The first one of these was installed in Boeing in 1982 and remains to be widely used.

Once the plane grounds, the ground crew unload the tank on the back of a truck and dispose of it at a treatment facility. Even if pilots or flight attendants did want to unload the tank mid-flight, they would be unable to as the valve is located on the plane’s exterior.